Case of the Costume Killer
by Aikidou
Summary: The BAU is asked to assist on a new case involving a serial killer who is slashing his victims throats at various conventions. This case will force the team to take a step far out of their comfort zone. Luckily, they have help. Rating suject to change.
1. Prologue

***Prologue***

It was Saturday night and Lora was tipsy. At least, that is how she would describe herself if asked. If truth be told, Lora was only a few drinks away from passing out. But she felt too good right now to care. She swayed her hips in time to the beat as the music blared from the large speakers and the strobe lights flashed. The pale pink wig and white embellishments on her costume practically glowed under the black lights that had been placed around the crowded room. It was hot, her clothes practically plastered against her skin and still she danced. Grinding and bumping with every person she could. She was drunk and just wanted to get laid. Which is why, when the man she was currently grinding her ass into suggested that they move things somewhere a little more private, Lora had no complaints.

"My roommates are going to be out all night" Lora said to the man as she turned, wrapping her arms around his neck and pressing herself completely against him. "Sounds like a plan" the man answered as he bent down and started nipping and kissing at her neck. They stayed like that, grinding into each other in time to the music until Lora eventually broke away. Taking the man's hand she lead him through the throng of dancers and out into the hall. The air in the hallway immediately sent shivers down her spine and she continued to lead her soon to be partner towards her room. Lora was once again grateful that the room was located on the second floor of the hotel, as they reached it in no time. Unlocking the door she pulled him in, placing her Hitai Ate over the outside handle to let her roommates know not to come in should they decide to return early. Closing the door, she grinned the turned on heel. Pressing herself against the man once more.

When Lora's roommates found her, she was lying in the center of one of the shared double beds. Her eyes glossed over and staring lifelessly at the ceiling. Her body and the bed beneath her coated in now dry blood. Her throat slashed wide open.

Author's Note:

*Hitai Ate: The clothe headband with a mental strip and symbol worn by ninja's in the anime Naruto. A prop that is very popular among cosplayers of all types.


	2. Chapter 1 The Case

Hey all! Thanks to everyone who is reading this fic. Especially those who have taken the time to review! *gives homemade Snickerdoodle cookies* I really must appologize for the typos the last chapter. Hopefully they're all fixed!

This fic is pure humor with a bit a crack and some drama. The idea for this fic came about on the way to Ohayocon and came from two sleep deprived and caffeine high people. If that bothers you, please don't send flames. Flames will be fed to Clooney. Constructive crit is ALWAYS welcome though!

Disclaimer: Criminal Minds is not mine. I'm writing this for fun and making not a single red cent off it.

Chapter 1 – The Case

Silence. Were one to enter the BAU conference room that is all they would hear as Jennifer – JJ – Jareau distributed the case files to each of her team mates. Normally the team would already have glanced over the board and be bouncing theories off each other by this point. Instead they were staring at the board in what could only be described as a mix of shock and confusion. Even Hotch, their stoic leader, was having trouble keeping a completely straight face. Only Spencer Reid seemed to be unfazed and was scanning the case file while the others gawked.

Taking her place at the front of the room, JJ began the briefing. "July of last year, Amy Sanders and Bridget Moore were both found dead in Baltimore, Maryland during a convention called Otakon. January of this year, Emma Higgins and Sandra Lang were found dead in Columbus , Ohio at another convention – Ohayocon. In February during Katsucon in DC, the bodies of Lora Weston and Amanda Edgley were discovered. All six victims were found in secluded areas of the convention, their throats slashed. The killings were spaced apart, one late Saturday night and the other Sunday afternoon. Each murder has taken place at an 'Anime' convention. Because the conventions are states apart, law enforcement officials didn't connect them until recently." As she finished, JJ stepped away from the board. The agents once again had an unobstructed view of the crime scene photos. The pictures peppered the board. Six young women forever immortalized in death, caught on film. Each girl was in one costume or another, now ruined by their own blood.

Derek Morgan was the first to break to awkward silence. "Anime?" he questioned, one brow raised. "It's short for Japanese Animation. It's an animation style which first became a pop culture main stream in 1964 with Osamu Tezuka's 'Astroboy'. Anime has sparked a huge subculture and fan base here in the United States since. As well as highly influenced American animation. Some even argue that the Disney movie 'The Lion King' is practically an American version of 'Kimba the White Lion' by Tezuka Pro. Which given – " Reid was cut off mid-rant by Morgan's next question. "So… cartoons?" At Reid's annoyed huff, Morgan amended himself, "Japanese Cartoons". Prentiss, who's eyes had been glued to the board with an almost horrific fascination, finally tore her gaze away and voiced the question that was on the forefront of most everyone's minds. "Why… are they… in costume?"

"It's called 'Cosplay" Honey." Garcia chimed in, having just arrived in a few moments before hand. "And it's kinda fun," she said with a smirk. All heads in the room turned towards her. "Baby-girl…" Morgan began, but found he didn't quite know how to finish. "Cosplay," Prentiss said as if testing the word. She then raised a hand in Reid's direction, effectively stemming off the flow of information she knew was about to spill forth. "No… I don't want to know." Reid shrugged, giving her a shy smile, before returning his attention to the case file in his hands. Once more, the room fell into silence before JJ spoke again. "So far the UnSub has hit only major conventions with attendance in the eight thousands and up range. The next convention that fits this category is Anime Central, held in Rosemont Convention Center which is located right outside of Chicago. Local law enforcement has asked us to step in."

Thus far, Hotch had remained quiet. He glanced over everything on the board and in the case file as JJ spoke. An odd sense of dread had started to build in his stomach since he was handed the file. Trying to mentally shake it off, he turned to his team. "Get your go-bags. We leave in one hour." As he turned and strode out of the room, he felt the dread settle like a rock in his gut.

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An hour and a half later found the team in the air, en-route to Chicago's O'Hare Airport where they would be met by the officers who had been assigned to the case. According to JJ, they would receive further briefing on the situation from said officers.

Sitting in the back of the jet, David Rossi watched his team mates under the guise of perusing the file once more. This was not their usual case and Rossi couldn't help but be slightly amused by the various reactions each team member was having to the unusual subject matter. JJ and Prentiss had pulled out a laptop and were doing some research of their own while Reid attempted to explain some of the various concepts of the "anime genre", as the young genius had called it, to Morgan. From where he was sitting, Rossi had heard words such as "Mecha", "Sentai", "Harem" – which had perked some curiosity – and "Magical Girl".

"Magical… girl? Pretty Boy, what the hell? And WHY do you know this stuff? I thought you were into Sci-Fi and what not." Morgan's head actually hurt at this point. He knew Reid was practically the human equivalent of an encyclopedia, but this was a bit much. It took geek-dom to a whole knew level in his opinion. Or maybe he just honestly didn't get it. With a mental shrug, Morgan tried to pay attention as Reid expanded on what was apparently one of the most popular genres. That was until a small shriek followed by an "OH MY GOD!" and the sound of the laptop slamming shut interrupted.

Hotch had been lost deep in thought, still perturbed by the unexplainable feeling of dread. His head snapped up immediately at the noise, attention refocusing to his agents. JJ was sporting a rather deep blush and Prentiss had a look of abject horror on her face. Both women turned slowly towards Reid, matching glares aimed the their resident genius. Reid seemed to be trying to disappear into his seat. And Hotch couldn't blame him. At that moment, the two women were terrifying. A soft nearly squeaked "What?" from Reid only caused their glares to intensify. After another moment or two, Prentiss finally spoke. "You failed to mention the porn." "There were tentacles…" JJ added. At that, Reid's eyes grew impossibly wide.

In the back of the jet, Rossi was chuckling quietly to himself. It would be interesting to see how Reid got himself out of this one.

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By the time they landed, Reid had decided that he was never making his female team mates angry again. Morgan had decided that FBI women didn't need a gun to be scary. And Rossi was officially very amused. They exited the jet to find an unmarked navy blue Crown Victoria parked on the tarmac. Leaning casually against the hood of the car was a young woman in a green button down shirt, black vest, and matching black pants. Over her shoulders was a deep brown shoulder holster, the CPD shield displayed prominently on the left strap. Seeing them approach, she stood and met them half way. Brushing dark curls behind an ear, she extended a hand to Hotch. "Agent Hotchner, I presume?"

Taking her extended hand, Hotch was almost surprised at the firm handshake he received. "SSA Aaron Hotchner. This is SSA David Rossi, SSA Derek Morgan, SSA Jennifer Jareau, SSA Emily Prentiss, and Dr. Spencer Reid." Hotch indicated each member of his team as he introduced them. "Detective Kathryn O'Conner, Chicago PD", the woman introduced herself with a smile. Rossi quirked a brow as he spoke "Detective… at your age?" Kathryn laughed good naturedly at his question. "I'm older than I look" she answered with a playful wink. "Before you ask… I'm 28," she finished with another smile.

To say the team was surprised would be an under statement. The women before them looked like she couldn't be older than 19. "I get that question all the time, so it's no big. Tends to come in handy most of the time." She added with a shrug. Rossi could see how that was possible, given that everyone present stood at least a good few inches over her. Morgan and Reid standing over a foot taller. Add in her rounded face and large green eyes… Rossi could definitely see how that was possible. She seemed oddly care free for a police detective though, which he found odd. As she led them back towards the car, Rossi decided he was going to have fun figuring this girl out.

"I must apologize. There were supposed to be two of us meeting you, but Dani had something come up on one of her cases so she's running a bit late." Kathryn explained as she popped the trunk of the Crown Vic and began moving a few things around in an effort to make some extra room. The sound of tires screeching around a near by corner caught her attention. Head popping up from it's previously stooped position with a small frown, "Well speak of the devil."

A fire-engine red four-door coupe came to an abrupt halt a few feet away. A moment later, the door opened and a tall very blonde woman stepped out. What caught the BAU team's attention however was how she was dressed. A vibrant purple Chinese top adorned her top half while a knee length black skirt, complete with large slits up the left side, and thigh high black boots covered her lower half. Her bright blonde hair was tied back in a messy bun, held by a pair of chopsticks. As she walked towards them, she removed a pair of large designer sunglasses .With a roll of her eyes, Kathryn stepped around the car and toward the other woman. Hands on her hips she practically glared at the blonde. " You were already running late. You couldn't take a little extra time to CHANGE?"

The blonde simply smirked. "As you said… I was already late." Turning back towards the BAU, the blonde introduced herself, "Detective Danielle McKorn". Hotch couldn't help but blink as both women turned towards his team. The two were almost exact opposites. The blonde stood almost a foot over the other woman. Where Kathryn was dark, Danielle was pale and visa versa. Even their personalities, from what he had seen thus far, were on complete opposite ends of the spectrum. He was even more surprised when the smaller woman proceeded to introduce his team.

Once she was finished, Danielle gave a "Nice t' meet ya!" and a wink at Reid. Reid proceeded to turn a very bright shade of red, which caused the tall blonde to laugh. Shaking her head in exasperation, Kathryn then looked back to the team with what Hotch could only describe as a concerned smile. "You probably want to get settled and start working. It's way past lunch, let's go grab something and Dani and I will read you in. Is Red Robbin's alright?"

"Red Robbin's?" At Prentiss' question, both CPD detectives looked aghast. "You've never been to a Red Robbin?!" Danielle voiced the question after a moment. "I guess that would make sense… Red's isn't in a lot of places yet." Kathryn explained, then added "It think you'll like it. And they can easily seat all of us. Come on… it will be our treat." At that, she gave another of what Rossi had already pegged as her signature smile, and made her way to the driver's side of the car. Peaking over the roof of the car, over which she could be barely seen, Kathryn spoke once more. "So… who's riding with whom?"


	3. Chapter 2 A Late Lunch

Hey everybody! Thanks so much for reading this. Once again, special thanks to my reviewers. You guys help keep my creative fire lit. I hope everyone enjoys this chapter as well. Please R&R! Constructive criticism is always welcome. Flames will be fed to Clooney.

**AN:** For some reason, this chapter went all wonky when I first uploaded it. Hopefully all the formatting problems have been fixed and everyone can enjoy! Special thanks to everyone who let me know about the issue.

**Disclaimer:** I don't own and I'm flat broke.

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*****Chapter 2 - A Late Lunch*** **

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The restaurant was spacious. It was vibrantly decorated, with walls covered in large bay windows that kept the atmosphere bright. Despite being oddly busy for that time of day, the group was seated immediately by the hostess. This was most likely due to the fact the hostess was on first name basis with the two CPD detectives. They were seated in the back at a large rectangular table, in an area that was partially partitioned off by a glass and wooden wall. Majority of the other customers were seated near the front of the restaurant and around the bar. Hotch wondered how much the detectives ate here that the staff automatically seated them in a more private location. The hostess passed out their menus, cheerfully informing them of the day's specials then stopping to talk to Det. O'Conner, whom Hotch heard the girl call "Kate". A few minutes later, the waitress excused herself with a chirped "Enjoy your meal!" Having noticed that Hotch had been observing the exchange, Kathryn smiled at him "Erica's in her third year of college, majoring in Social Work. We both volunteer at a local center for victims of abuse." She explained. "She's a good kid. One of the sadly few success stories of the foster system. She keeps her nose to the grind stone and I could see her becoming head of DCFS one day." Hotch noticed that the brunette had failed to mention the type of abuse victims she volunteered with and something told him not to ask. Instead he picked up his menu and started looking it over. A sharp "Dani! Leave him alone!" snapped from the O'conner startled Hotch out of his inner musings. Head snapping up, Hotch followed the Irish detective's line of sight to see that McKorn had plopped herself down next to Reid and was doing a very good job of invading his personal space. He couldn't hear what was being said, but got the feeling that the blonde woman was teasing the genius by the color Reid's face was steadily turning. Sharing an amused look with Rossi, Hotch allowed himself small grin as he turned back to his menu. The sound of Reid's squeaked protests and his team's laughter lifting the feeling in his gut.

Morgan watched Reid and McKron for a while before turning his attention to the smaller of the two women, seated across from him. "So… Detective, what's good?" he asked in his usual playful manner as he held up the menu. Kathryn quirked a brow as she answered. "Detective? Well aren't we the formal one." Then with a smile, "As for what's good… well that depends on what you're in the mood for". Morgan smirked, but before he could comment she continued. "I usually go with the stir-fry bowl, but the Red's Royal Burger is good if you want something a little out of the ordinary. I highly recommend the Freckled Lemonade. It's sweet with just the right amount of tart. Have to be careful though… over indulge and it can bite." Morgan blinked… had she actually just said all that with a straight face? He had no idea whether he was being flirted with or receiving genuine recommendations. Instead of dwelling on it, Morgan focused back on the menu. Reading over the descriptions he decided that the lemonade she'd recommended actually sounded pretty good. After making his decision, he refocused his attention on the spectacle that was an extremely nervous and embarrassed Reid.

Reid was not in a happy place. He was used to JJ, Garcia, and occasionally Prentiss and Morgan invading his personal space. Having a complete stranger do so made him extremely uncomfortable. Reid fidgeted as McKorn leaned in and looked at the menu over his shoulder. Despite having a menu of her own she was insistent on looking at his. When Kathryn had scolded her, Danielle had retreated for a moment before leaning back in to point out something on the menu. There was a gleam in the blonde's eyes that was making him rather uneasy. In an attempt to turn the focus of attention away from himself, Reid tried making conversation, "McKron… that's of Scottish origin, isn't it?" Danielle grinned and replied "Yep. Reid's an Irish name right? That mean you're lucky?" On 'lucky' she had given him a wink which caused Reid to turn a whole new shade of red. Giggling, Danielle finally leaned back. Apparently having decided he'd had enough teasing for now. When Danielle stood and moved to sit in the empty chair next to Kathryn, Reid allowed himself to relax.

Their waiter, whom the detectives also seemed to know, came and took their orders before returning after a few minutes with their drinks. Rossi took note of the fact that both of their CPD hosts had ordered what he had heard referred to as 'the Freckled Lemonade'. As had Morgan, which surprised him. Rossi watched as the small brunette mashed the strawberries in the bottom of her glass with straw before stirring the drink and picking them out, handing the fruit to her coworker beside her. "That's interesting…" he thought to himself. The two women were obviously very familiar with each other, judging by how they interacted. They're personalities where extremely similar on many levels, yet complete opposites on others. Both were obviously very social. Rossi suspected strong alpha tendencies as well. However, where McKorn was boisterous and In-Your-Face, O'Conner displayed more of a quiet strength. It would be interesting to see how they balanced a leadership role between them. Glancing over at Hotch, he could tell the other agent's thoughts were currently working along the same line.

Once their meals arrived, majority of conversation came to a pause as the BAU team tucked in. Prentiss hadn't realized how hungry she was until the food was placed before her. All of her attention had been on their current case as she tried to work things out in her mind. Everything about this case was odd and for the first time since she was new to the team, she found herself feeling nervous. The fact that neither of the detectives had identified which division they were with when introducing themselves had also set her nerves on edge. Prentiss had met a lot of cops in her life, mostly because of her Mother's work and her own experience at the FBI. Officers almost always included what division they were with when introducing themselves to other agencies. The exception being the hand full of officers in units where revealing such information in public could put themselves or a case in jeopardy. This usually meant they were in some form of undercover unit, possibly even Deep Cover. Prentiss had only known a couple of Deep Cover officers and both had been completely different from the other, which made assigning a personality type impossible. She would never peg the CPD detectives as Deep Cover, but then that would be what made them good at their job. Prentiss noticed Morgan studying them as he ate and covertly pulled out her cell, shooting him a quick text. _'What do u think? DC?'_ She watched as Morgan pulled out his phone, looked at her message and grinned. His answer of _'Hell yes' _arrived a minute later. JJ, who had noticed the exchange, gave Prentiss a curious look. Prentiss leaned over and whispered "later" to her friend, seated next to her.

Once their plates had been cleared and drink refilled, O'Conner proceeded to pull several file folders from the canvas tote she had brought with her. Handing one to each person at the table, she began the briefing. "This is all of the information on the killings that we have, gathered from each of the stations that responded to the scenes. I assume you most likely already have a majority of this. The coroner's report and autopsy results have been included, as have all crime scene photos and profiles on the victims. From the few witness statements that exist, we know that we are looking for a Caucasian male in his early to mid twenties." It was here that O'Conner paused and McKorn began speaking. "This information is extremely unhelpful from an investigation stand point given the sheer number of people who attend the conventions. Based on that information alone, we are looking for one in about three thousand. Going by his M.O. we are fairly certain he will be at Anime Central. Anime Central is the major convention for the Midwest and draws its attendance from as far as Canada and Mexico. This means that our best chance of catching the perp is at the convention. If we don't catch him this weekend, then he goes back to where ever he is from and it will be up to the Los Angeles PD to catch him in July. And that is only if he hits major conventions."

Everyone at the table had noticed the immediate change in the detective's behavior once they had started the briefing. Both were sitting up straight, completely focused and professional. Even the tones of their voice and the manners in which they spoke had changed, becoming deadly serious. Neither were smiling, instead their mouths were set in a firm line. It was as if someone had flipped a switch on their personalities. The team listened intently, switching their focus to Kathryn as she once again spoke. "Convention staff has been alerted and is more than willing to work with us. The CPD realizes that this is an unusual case and will most likely place you in situations that you are unfamiliar with. That is why Dani and I have been assigned to work with you. Both of us are familiar with the convention, or 'con', atmosphere and are here to act as guides. My last case closed a few days ago, so I will be with you full time. Dani may have to leave on occasion to deal with a currently ongoing case but will be with us a majority of the time. Many convention goers are not likely to open up to anyone preserved as outsiders. A select few will be downright dishonest. Most are friendly, but getting inside information would be like pulling teeth. In our opinion the best way to catch this perp would be to split into two groups, one accessing and observing from the outside, the other from the inside."

A pregnant pause over took the table. The detectives waiting for the opinions of the FBI team seated with them as the agents digested the information. Eventually, it was JJ who broke the silence, "When you say 'inside' you mean…?" It was Danielle who answered.

"Undercover."

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**Author's Notes:**

Okay… I have no idea if Chicago actually has a Deep Cover division, but I am taking some creative license. So in this fic, they do.

Perp = Short for Perpetrator. Its cop slang. Anyone who watches Law and Order should be familiar with that one.

M.O. = Modus Operandi aka the method of operation. Basically how the crime was committed. If you are a CM fan and don't know this one…

DCFS = Department of Child and Family Services


End file.
